Device, system and method for monitoring electromagnetic fields

ABSTRACT

A system for monitoring the electromagnetic field strength received at a predetermined point of a monitored area, includes a device that senses the electromagnetic field fed in at a least one frequency band to an antenna by a transmission apparatus and transmits at least one RF power signal indicative of electromagnetic field strength to a control center. With the control center a geographic data base is available that includes information items on the mutual position of the antenna and the predetermined point. A processing facility with the control center is configured for receiving the RF power signal from the device and calculating from the RF power signal and the data base items the field strength received at said predetermined point from the antenna.

FIELD OF THE INVENTION

The present invention relates to techniques for monitoringelectromagnetic fields and was developed by paying specific attention tothe possible application to monitoring the level or strength of ambientelectromagnetic fields.

DESCRIPTION OF THE RELATED ART

In EP-A-1 233 273, a device for monitoring electromagnetic fields isdisclosed comprising a reception chain capable of generating at leastone signal that is indicative of the electromagnetic field strengthmeasured by an antenna element. A threshold comparator element comparesthe field strength signal with a predetermined threshold. The thresholdlevel of the threshold comparator is selectively variable. A selectorelement renders the device selectively sensitive to the electromagneticfield in at least two different frequency bands. A communicationinterface is also provided so that data can be transmitted to and/orfrom the device thus permitting e.g. the selected band and/or thethreshold level used for monitoring to be varied selectively from aremote station.

Such a prior art device is intended to meet the growing concern aboutexposure to electromagnetic fields especially in connection with sourcessuch as:

radio and/or television transmitters (which, in urban areas with largeconcentrations of broadcasters are among the most significant sources ofelectromagnetic pollution), and

communication system transmitters, e.g., for mobile telephony.

Regulations are being adopted in a number of countries—such as forinstances the so-called ICNIRP Guidelines for limiting exposure totime-varying electric, magnetic, and electromagnetic fields (up to 300GHz)—that set a limit e.g. to the transit power over a defined timeinterval (for instance 6 minutes).

OBJECT AND SUMMARY OF THE INVENTION

The object of the invention is to further improve prior artelectromagnetic field monitoring arrangements. This permits notionalreal-time control of electromagnetic field intensity, by paying specificattention to the possibility of devising integrated systems adapted topermit proper electromagnetic field power management over a given area.

Moreover, object of present invention is a device, system and methoddirected at ensuring that established maximum levels are not exceededand/or that at any point in the area under control the field level issatisfactory for providing the expected quality of service.

According to the present invention, such an object is achieved by meansof a device having the features set forth in the claims that follows.The invention also relates to a related system and method.

In a possible preferred embodiment, the device of the invention acts asa sort of electromagnetic “fuse” adapted to reduce the power emission orde-activate an electromagnetic field source (such as a base station in amobile telecommunications and/or broadcast network) if theelectromagnetic field is found to exceed a predetermined maximum level.

Advantageously, the device of the invention can be used as a power meteradapted for sending to a control centre the results of RF powermeasurements, possibly in the form of average measurements over giventime intervals. In addition to the proper measurement circuitry, a RFpower meter device according to the invention preferably includes amicroprocessor and a communication interface such as a GSM modem whichtransmits such data to a remote control centre. This may occur via asuitable syntax through a SMS messaging system over a mobile telephonenetwork.

The control centre is in turn able to similarly communicate with thedevice. The results received at the control centre are stored andmanaged automatically.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example only, withreference to the annexed figures of drawing, wherein:

FIG. 1 is a schematic representation of the general arrangement of anelectromagnetic field monitoring system)

FIG. 2 is a block diagram showing a RF power monitoring device asassociated to an electromagnetic field source such as a base station ina mobile telecommunications system,

FIG. 3 is block diagram of the RF power monitoring device shown in FIG.2,

FIG. 4 is a time diagram showing RF power measurements carried out inthe system described herein,

FIG. 5 is a flow chart further explaining how RF power measurements areperformed, and

FIG. 6 is the flow chart which details the complete procedure toevaluate the electromagnetic field.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

In FIG. 1, reference 1 generally designates a source of electromagneticfield such as, e.g. a base station (BTS) included in a mobiletelecommunications system or a broadband transmitter.

Reference to a base station such as a BTS station is of exemplary natureonly and must in no way be construed as limiting scope of the presentinvention, which is in fact adapted for use in connection with anysource of electromagnetic fields, in particular for telecommunications.

More in detail, the station 1 includes one or more antennas 2 fed with aRF signal over a feeder 3 from a transmitter assembly 4 of a known typehaving associated a RF power monitoring device 5.

As shown in FIG. 2, the transmitter assembly 4 includes a number oftransmitters TX1, TX2, TX3 . . . , TXn each transmitting over arespective frequency band. The output signals from the varioustransmitters in question are combined in a mixer 6 to be transferred tothe antenna (s) via the feeder 3. This usually occurs via a directionalcoupler 7 from which a monitor line 8 a is derived.

On the monitor line 8 a signals are present (typically in the form oflow-level RF signals) whose intensities are a function—usuallyproportional—of the intensities of the RF signals sent towards theantenna (s) 2 in the various frequency bands concerned.

By knowing other parameters of the station 1, such as the power lossalong the feeder 3 as well as cartographic information of a site, thesignals on the monitoring line 8 a are thus indicative of the strengthof the electromagnetic fields transmitted from the antenna (s) 2 in eachand every band covered by the transmitters TX1, TX2, TX3 . . . , TXn.

In other words, the RF power measurements are indicative of theelectromagnetic field in the geographic area covered by the antenna (2).

The control line 8 b connects the monitoring device 5 to the powercontrol device 9 of the BTS. The BTS could decrease or even shutdown thesignal injected in the antenna under commands sent, for example, fromthe monitoring device 5.

According to further embodiments of present invention, the device 5 canbe associated either to a plurality of antennas or to a plurality ofbase stations or broadband transmitters.

Moreover, the device 5 can be integrated or associated, in known way,either into/to the antenna 2 or into/to the transmitter assembly 4.

By referring now to the block diagram of FIG. 3, the signals over themonitoring line 8 a are sent towards one or more filters banks 10 a, 10b each including a number of input channels for receiving the monitoringsignals from the transmitter 4.

Two banks of filters 10 a, 10 b being shown herein is due to the currentavailability of this arrangement as a standard component and must in noway be construed as limiting the scope of the invention.

Each input channel in the filter banks 10 a, 10 b is adapted forreceiving RF signals, in the frequency band of one of the transmittersin the station 1. For that reason, in the block diagram of FIG. 3, thoseinput channels are simply labelled with the same references TX1, TX2,TX3 . . . , TXn designating those transmitters.

Each input channel generally includes an (optional) filter 11 forperforming a band pass filtering action to possibly dispense withinterference from other channels as well as a RF rectifier 12. Therectifier 12, for example an AD8361 of ANALOG DEVICES, is cascaded tothe filter 11 to produce an analogue DC signal whose value isproportional to the root mean squared (RMS) of the input signals; inother word the output DC signal is indicative of the global RF power intransit over the input channels TX1, TX2, TX3, TXn.

The output line from each RF rectifier 12 is brought to a correspondingswitch 13 controlled by logic input signals D6, D7. Two such switches 13are shown herein due to the filter banks 10 a and 10 b being arranged inparallel.

The (analogue) output signals A1, A2 selected by the switches 13 are fedto an input/output interface 14 adapted to interface the circuitrydescribed in the foregoing with the processing unit 15 including aprocessing device such as a microprocessor 16.

Any of the rectified signals produced by the various RF rectifiers 12may thus be caused to appear at the output of the interface 14.

Within the processing unit 15, reference 17 designates ananalogue-to-digital converter for converting the analogue signals A1, A2as received at the interface 14 into corresponding digital signals to befed to the microprocessor 16 for processing.

The microprocessor 16 also includes a number of output control lines D3to D8, including lines D6 and D7 that control the switches 13.

Reference 18 designates a communication module such as GSM modem fortransmitting signals from/to the microprocessor 16 (and the device 5 atlarge).

Reference 19 designates the AC/DC power supply feeding the variouscircuits described in the foregoing.

Essentially, the microprocessor 16 controls the various logical gates inthe device, senses and measures the values of the two monitoring signalsA1, A2 possibly storing the respective values thereof in an associatedmemory (not shown, but of a known type) in order to process them andsend the results to a remote control centre 20 (FIG. 1) via thecommunication module 18. As indicated, this is preferably configured asa GSM modem thus permitting communication to and from the remote controlcentre 20 to take place via SMS messaging.

The microprocessor controls also the control line 8 b that communicateswith the power control 9; this control line 8 b is used bymicroprocessor 16 for controlling, in a way well known in the art andwhich is not necessary to be described herein, the decrease or shutdownof the RF power injected in the antenna 2 when precise conditions aremet.

In particular, the microprocessor 16, by using a control module storedinto the associated memory or commands received from the control centre20, as will be described later on, is able to control the RF powerinjected into the antenna 2.

A presently preferred embodiment of the device 5 provides, for example,that the RF input power is converted into DC signals A1, A2; such DCsignals A1, A2 are proportional to the RF power according to apredetermined ratio.

Therefore, the DC signals A1, A2, are proportional to theelectromagnetic field intensity generated by the antenna 2 associated tothe device 5.

Still preferably, the logic control signals D6, D7 to the switches 13are generated in such a way that the output signals A1, A2 sequentiallycorrespond to the various RF input signals to the filter banks 10 a, 10b at the various frequencies.

In a preferred embodiment, the device 5 will also includes a temperaturesensor 21 which is controlled together with the power supply 19 viamicroprocessor outputs D5, D6, D7. The output lines D3 and D4 areusually adapted to control display units (such as LEDs) that are adaptedto be activated as a result of the measured field signal having reacheda threshold. Reference 22 indicates a monitor connector.

The graph of FIG. 4 shows a typical measurement cycle carried out bycontrolling the logical outputs D6 and D7 of the microprocessor 16 inorder to acquire the voltage on the two analogue channels A1 and A2.

In the example shown (this is recalled to be just an example), sensingthe voltage at the output of the interface 14 is carried out byinitially setting the outputs D6 and D7 at reference values (e.g. thezero values) during the “active” portion of a cycle of the clock signal(exemplified by D8) and subsequently switching to “one” the D7 signalfrom the microprocessor 16.

The results thus obtained are memorized in the memory of themicroprocessor 16. The sampling time is a significant parameter. It isin fact necessary to determine precisely the intervals required forperforming the three phases (setting of the logical outputs, acquisitionproper, storing the results) comprising the measurement cycle.

As shown in FIG. 4, most of the time within the cycle is devoted tostoring the results, which may require e.g. 7 ms, while setting thelogical outputs D6 and D7 and acquiring the DC voltage may require e.g.244 microseconds.

In fact, in the presence of such a short sampling times, a sort ofaveraging action may be beneficial.

The typical sampling time as shown in FIG. 4 is about 10 ms andstandards such as the ICNIRP standard referred to in the introductoryportion of the description indicate a typical measurement time of 6minutes. These values would at least notionally lead to 36,000 differentsamples being collected and stored for each transmitter TX1, TX2, TX3 .. . , TXn. Such a high number of samples would render storing theresults unnecessary critical.

For that reason a preferred embodiment of the invention provides thatthe samples collected each 10 ms be averaged over a time interval ofe.g. one second. The average values thus computed are then stored. Inthat way, in the case of the six minutes considered in the ICNIRPstandard, for example, only 360 average values are stored, thus makingmanaging of the memory in the microprocessor 16 much easier.

In the preferred embodiment, a number of averaged samples slightly lessthan 360, such as 354 are stored. This is due to the additional time forcomputing the average value which is approximately 17 ms at each second.

The average of these 354 samples of the RF power injected, for example,can be evaluated immediately with a power threshold value eithermemorized in the memory associated to the microprocessor 16 or receivedfrom the control centre 20; should they exceed the threshold value, themicroprocessor 16 will operate the reduction or the shutdown of thepower using the power control 9 via the control line 8 b. In this casethe device 5 acts as a local or remote “fuse” and will inform, by meansof the communication module 18, the control centre 20 of this action.

The results stored in the memory associated with the microprocessor 16are then sent to the control centre 20. This is preferably comprised ofa personal computer 24 connected via an RS232 interface to a GSMterminal (modem) 25 adapted for communication with the GSM modem 18provided in the device 5.

In operation of the system shown in FIG. 1, the control centre 20periodically requests updated measurement data from the device 5. Therequest may be conveyed by a short message (SM) sent by the terminal 25towards the device 5 and, more specifically, the modem 18.

The syntax of such a message preferably includes information concerningthe time of day for starting and completing measurements, the RF inputs(TX1, TX2, TX3, or TXn) to be measured and so on.

Upon receiving the short message conveying the request, the device 5sends to the control centre 20 another short message acknowledgingreceipt of the request. The device 5 subsequently carries out ameasurement cycle along the lines described in the foregoing. Theresults are subsequently sent to the control centre 20 again in the formof one or more short messages.

In addition to sending the short message prompting each measurementcycle, the personal computer 24 ascertains the possible presence of newmessages at the terminal 25 and, in the positive, stores them in view ofsubsequent processing. The possibility also exists of forwarding theshort messages received from the device 5 towards another controlcentre, a given telephone number or a given e-mail address.

The flow chart of FIG. 5 exemplifies in general terms operation of thedevice 5.

In a step 100, the device 5 periodically checks whether new requests arereceived from the control centre 20. This step is performed e.g. everytwenty seconds.

Upon receiving such a message conveying a measurement request, thedevice 5 sends an acknowledgement message towards the centre 20 and thenstarts the measurement phase proper, which is designated 102 as a whole.During such a phase, the device 5 collects the measurement data andcomputes the average values thereof as explained in the foregoing whilealso sending the results towards the control centre 20 in the form ofshort messages. Preferably, the phase 102 involves computation of amoving average of the results sent, e.g. such a moving average beingcomputed every minute in a total measurement interval of six minutes.

Intervals at which the results are sent towards the control centre canbe selected in order to best exploit the communication facilitiesexisting between the device 5 and the control centre 20. Consequently,those results can be sent at intervals of, e.g., 3, 4, 5, 10 minutesdepending on the specific needs to be met.

In a step 104 the device 5 checks whether a message indicating that themeasurements are to be interrupted has been received from the controlcentre 20. The device 5 is thus reset to the wait step 100 in the caseof a positive result. In the negative, in a step 106, the device 5further checks whether the final time for completing measurements, asindicated in the original message received from the control centre 20,have been reached. In the positive, the device 5 evolves back to thewait step 100. In the negative, operation of the device 5 furtherevolves to the measurement phase 102.

The personal computer 24 is configured in such a way to coordinateco-operation with one or more devices 5 associated with respectivesources of electromagnetic fields such as base station, transmitters,and so on.

Essentially, the personal computer 24 performs the following functions:

selecting and setting the serial gate connected to the GSM terminal 25,

sending single commands for co-operating with the terminal 25,

sending short messages,

automatically receiving short messages,

storing (e.g. on hard disk) the results received from the device(s) 5,and

displaying the results received.

The computer 24 may also include one or more databases containinginformation on the various devices 5 (anagraphic information, respectiveSIM numbers of the GSM modems associated therewith and so on).

In a particularly preferred embodiment of the invention, such databasesmay include specific information concerning the or each antenna 2 suchas e.g. the attenuation values of the feeders 3 and the circuitsassociated therewith (directional coupler 7 and so on).

Based on this information, and the measurement data received from thedevice 5, the personal computer 24 is thus in a position to compute thefield strength emitted at a given time (or over a given period oftime—as indicated, this may be in the form of the average value over agiven time interval of e.g. 6 minutes) by the or each antenna 2monitored, possibly for each and every frequency band covered by thetransmitters TX1, TX2, TX . . . , TXn.

The availability of additional geographical information concerning thelocation of the antenna 2 and specific propagation characteristicsassociated thereto within a certain area being monitored also permitsthe expected field strength at any given point of that area to beevaluated.

In the flow chart of FIG. 6, reference 200 designates the step where the(or each) device 5 connected to a given control centre 20 collects datacorresponding to the electromagnetic field strength emitted by arespective antenna 2 over a given frequency band at a given instance oftime (e.g. over a given time interval).

In a step 202, these results are sent from the or each device 5 to thecontrol centre 20 as a value of the transit power 204 at the respectiveantenna.

These data are adapted to be processed jointly with other data itemsavailable at the control centre 20. These additional data itemstypically include:

the geographical coordinates (as derived from a data base designated206) of any point within the area subject to monitoring where theelectromagnetic field strength is to be evaluated,

a cartographic data base (designated 208) containing informationconcerning the location of the or any antenna 2 within the area subjectto monitoring and specific propagation characteristics associatedthereto within a certain area, and

another data base designated 210 grouping records concerning thecharacteristics of the antenna(s) 2 such as the attenuation values ofthe feeders 3 and the circuits associated therewith.

More specifically, the cartographic data base 208 includes informationin a raster and/or vector format concerning the terrain and buildingswithin the area subject to monitoring.

The antenna data base 210 generally includes information concerning:

the geographic coordinates and altitudes of the antennas,

the aiming direction (azimuth, elevation),

the antenna gain,

the radiation diagrams in the main planes (vertical, horizontal),

the maximum RF output power from the base station towards the antenna,

the loss figures of the cables/waveguides between the base station andthe antenna (feeder).

The antenna data base 210 shall also include the attenuation valuerelating the power output from the base station towards the antenna tothe power output from the base station towards the measuring device.

Following a step 212 marking the start of the measurement cycle, in aprocessing step 214 the computer 24 computes (in a manner known per se)the value of field strength present at any point 26 (FIG. 1, FIG. 6))identified by the coordinates taken from the data base 206 as a functionof the power level detected by each device 5.

In fact, the power level(s) detected by the device(s) 5 in a givenfrequency band can be directly related—on the basis of the informationstored in the data base 210—to the electromagnetic field emitted by theor each antenna 2 in a given frequency band.

Since the position of the or each antenna is known (as recorded in thegeographic data base 208) and the coordinates of the point at which thefield strength to is be evaluated are similarly known (as recorded inthe data base 206), the field strength in question can be computed onthe basis of propagation calculations thus leading to correspondingfield strength value to be made available in a step 216. Advantageously,the method disclosed in WO-A-02/095428 can be used for that purpose. Thesystem may be extended to include a plurality of devices 5 associatedwith antennas 2 of a respective plurality of antennas which jointly“cover” a given area. The devices 5 thus provide respective RF powersignals to the control centre 20. The personal computer 24 is configuredfor calculating, from the RF power signals received from the variousdevices 5 and the information items in the geographic data base 206,208, the electromagnetic field strength at any point 26 of the areacovered, such electromagnetic field resulting from the superposition ofthe electromagnetic fields emitted by the various antennas.

In any case, the accuracy of the value determined in the step 216 may bechecked by way of direct comparison with the field strength possiblymeasured “on the field” by means of a device as disclosed in EP-A-1 233273, the results of such a comparison being selectively available fordifferent frequency bands/ranges. The precision of the values providedby the system just described may thus be measured and the computationaltools used in the computer 24 correspondingly refined.

An upper limit value for the field strength at a given point of the areamonitored, as read in a step 218, may thus be compared in a step 220with the value calculated during the processing step 212.

The upper limit in question may identify an upper limit (for instance 20V/m) as a maximum value not to be exceeded at any time at any point inthe area under control of course, such a comparison can be carried outselectively by distinctly referring to a given upper limit for eachfrequency band in which the field strength is evaluated.

In the case the upper limit in question is not exceeded (negativeoutcome of the comparison step 220) operation of the computer 24 simplyloops back to the start step 214.

Alternatively, if the comparison 220 shows that the upper limit inquestion is reached, operation of the computer 24 evolves to an alarmphase 222 which may lead to a number of interventions such as, e.g.:

an alarm signal is sent to the operator and/or a control centre of thesystem to which the antenna (s) responsible for the unduly high fieldstrength belongs,

a control signal is sent to the device 5 associated with the antenna inquestion, causing the device 5 to act as a remote “fuse” in order toreduce the electromagnetic field emitted within a given frequency bandfrom one or more of antennas towards the point where the field strengthis evaluated; such an intervention of device 5, which may even lead tothe corresponding transmitter 4 to be shutdown, is carried out accordingto the method already described before. Advantageously, the controlsignal in question can be sent from the control centre 20 to the or eachdevice 5 by exploiting the same link (for instance GSM short messagesignalling) adopted for sending to the device 5 the messages orderingmeasurement processes to be started and for collecting field strengthdata from the device.

After this, operation of the computer 24 evolves to a stop stepdesignated 224.

In a complementary manner to what has been just described, the remotefield strength monitoring arrangement just described may be operatedwith the purpose of ensuring that the field strength at any point of thearea under control reaches a minimum level required to ensure a givenquality of service, with the additional possibility of selectivelyincreasing (through the device 5 associated therewith) the power emittedfrom one or more antennas in order to ensure proper field coverage ofthe whole area.

Of course, without prejudice to the underlying principles of theinvention, the details and embodiments may vary, also significantly,with respect to those that have been described and shown herein just byway of example, without departing from the scope of the invention asdefined by the annexed claims.

1. A device for monitoring the electromagnetic field emitted by anantenna, the device comprising: a measurement arrangement for measuringat least one RF power signal input to the antenna in at least onefrequency band, wherein said at least one RF power signal is indicativeof the electromagnetic field strength emitted by the antenna over agiven area; a communication module for transmitting said at least one RFpower signal measurement to a remote processing facility, wherein thecommunication module is configured to receive a power control commandfrom the remote processing facility, wherein the power control commandis based on at least cartographic information about the given area; anda control module configured to control, in response to the power controlcommand received from the remote processing facility, an intensity ofthe at least one RF power signal input to the antenna.
 2. The device ofclaim 1, wherein said measurement arrangement comprises a samplingcircuit responsive to the at least one RF power signal input to theantenna, the sampling circuit generating a sequence of samplesindicative of the electromagnetic field strength over a given timeinterval.
 3. The device of claim 2, wherein: said sampling circuitgenerates a first set of samples indicative of the electromagnetic fieldstrength over a given time interval, said measurement arrangementcomprises an average calculating circuit to generate a signal indicativeof the average electromagnetic field strength over a given timeinterval, and said average calculating circuit is configured foraveraging sub sets of said first set of samples so as to generate asecond set of averaged samples, said second set of averaged samplescomprising a number of samples that is smaller than the number ofsamples comprised in said first set of samples.
 4. The device of claim3, wherein the device further comprises a memory for storing datarepresentative of said at least one RF power signal, said memory beingarranged to store at least said second set of samples.
 5. The device ofclaim 1, wherein said measurement arrangement comprises an averagecalculating circuit to generate signals indicative of the averageelectromagnetic field strength over a given time interval.
 6. The deviceof claim 1, wherein the device further comprises a memory for storingdata representative of said at least one RF power signal.
 7. The deviceof claim 1, wherein said measurement arrangement comprises a pluralityof measuring channels, each measuring channel for measuring RF powersignals input to said antenna in a respective frequency band.
 8. Thedevice of claim 7, wherein the device further comprises at least oneswitch for selectively feeding towards said communication module theoutput signal of any of said measuring channels, whereby RF powersignals respectively indicative of electromagnetic field strengthsemitted by said antenna for each of said frequency bands are adapted tobe transmitted from the device.
 9. The device of claim 1, wherein thecommunication module transmits said at least one RF power signal to theremote processing facility using a wireless communication protocol. 10.The device of claim 1, wherein the antenna is positioned at a fixedlocation.
 11. The device of claim 10, wherein the measurementarrangement measures at least one RF power signal input to a pluralityof antennas positioned at the fixed location.
 12. A transmissionapparatus comprising a device for monitoring an electromagnetic fieldemitted by a antenna, the transmission apparatus emitting at least oneRF power signal to the antenna, the device comprising: a measurementarrangement for measuring the at least one RF power signal input to theantenna in at least one frequency band, wherein said at least one RFpower signal is indicative of the electromagnetic field strength emittedby the antenna over a given area; a communication module fortransmitting said at least one RF power signal measurement to a remoteprocessing facility, wherein the communication module is configured toreceive a power control command from the remote processing facility,wherein the power control command is based on at least cartographicinformation about the given area; and a control module configured tocontrol, in response to the power control command received from theremote processing facility, an intensity of the at least one RF powersignal input to the antenna.
 13. The transmission apparatus of claim 12,wherein the communication module transmits said at least one RF powersignal to the remote processing facility using a wireless communicationprotocol.
 14. The transmission apparatus of claim 12, wherein theantenna is positioned at a fixed location.
 15. The transmissionapparatus of claim 14, wherein the measurement arrangement measures atleast one RF power signal input to a plurality of antennas positioned atthe fixed location.
 16. An antenna comprising a device for monitoring anelectromagnetic field emitted by the antenna, the device comprising: ameasurement arrangement for measuring at least one RF power signal inputto the antenna in at least one frequency band, wherein said at least oneRF power signal is indicative of the electromagnetic field strengthemitted by the antenna over a given area a communication module fortransmitting said at least one RF power signal measurement to a remoteprocessing facility, wherein the communication module is configured toreceive a power control command from the remote processing facility,wherein the power control command is based on at least cartographicinformation about the given area; and a control module configured tocontrol, in response to the power control command received from theremote processing facility, an intensity of the at least one RF powersignal input to the antenna.
 17. The antenna of claim 16, wherein thecommunication module transmits said at least one RF power signal to theremote processing facility using a wireless communication protocol. 18.The antenna of claim 16, wherein the antenna is positioned at a fixedlocation.
 19. The antenna of claim 18, wherein the measurementarrangement measures at least one RF power signal input to a pluralityof antennas positioned at the fixed location.